489 research outputs found

    Determination of parasite resistance status to anthelmintics through the larval development test.

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    The control of gastrointestinal nematodes of small ruminants has been carried out through intense and indiscriminate use of anthelmintics.Boletim de Indústria Animal, v. 74

    Detection of bacterial contaminants by the larval development test.

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    The resistance diagnosis of gastrointestinal nematodes of sheep and goats to commercial anthelmintics is an important tool to guide farmers about the use of the most effective dewormer in their flocks, promoting sustainable production.Boletim de Indústria Animal, v. 74

    Gated cardiac CT in infants: What can we expect from deep learning image reconstruction algorithm?

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    ECG-gated cardiac CT is now widely used in infants with congenital heart disease (CHD). Deep Learning Image Reconstruction (DLIR) could improve image quality while minimizing the radiation dose. To define the potential dose reduction using DLIR with an anthropomorphic phantom. An anthropomorphic pediatric phantom was scanned with an ECG-gated cardiac CT at four dose levels. Images were reconstructed with an iterative and a deep-learning reconstruction algorithm (ASIR-V and DLIR). Detectability of high-contrast vessels were computed using a mathematical observer. Discrimination between two vessels was assessed by measuring the CT spatial resolution. The potential dose reduction while keeping a similar level of image quality was assessed. DLIR-H enhances detectability by 2.4% and discrimination performances by 20.9% in comparison with ASIR-V 50. To maintain a similar level of detection, the dose could be reduced by 64% using high-strength DLIR in comparison with ASIR-V50. DLIR offers the potential for a substantial dose reduction while preserving image quality compared to ASIR-V

    Diversity and hierarchy in supramolecular assemblies of triphenylalanine: from laminated helical ribbons to toroids

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    Microstructures from small phenylalanine-based peptides have attracted great attention lately because these compounds are considered to be a new class of tunable materials. In spite of the extensive studies on uncapped diphenylalanine and tetraphenylalanine peptides, studies on the self-assembly of uncapped triphenylananine (FFF) are very scarce and nonsystematic. In this work, we demonstrate that FFF assemblies can organize in a wide number of well-defined supramolecular structures, which include laminated helical-ribbons, leaflike dendrimers, doughnut-, needle-, and flower-shapes. These organizations are produced by the attractive or repulsive interactions between already formed assemblies and therefore can be controlled through the choice of solvents used as the incubation medium. Thus, the formation of the desired supramolecular structures is regulated through the protonation/deprotonation of the terminal groups, the polarity of the incubation medium, which affects both peptide···solvent interactions and the cavity solvation energy (i.e., solvent···solvent interactions), and the steric interactions between own assemblies that act as building blocks. Finally, the ß-sheet disposition in the latter structural motifs has been examined using both theoretical calculations and Fourier transform infrared spectroscopy. Results indicate that FFF molecules can adopt both parallel and antiparallel ß-sheets. However, the former one is the most energetically favored because of the formation of p–p stacking interactions between the aromatic rings of hydrogen-bonded strands.Preprin

    The association between MPOWER tobacco control policies and adolescent smoking across 36 countries: An ecological study over time (2006–2014)

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    Objective: To examine associations over time between national tobacco control policies and adolescent smoking prevalence in Europe and Canada. Design: In this ecological study, national tobacco control policies (MPOWER measures, as derived from WHO data) in 36 countries and their changes over time were related to national-level adolescent smoking rates (as derived from the Health Behaviour in School-aged Children study, 2006-2014). MPOWER measures included were: Protecting people from tobacco smoke (P), offering help to quit tobacco use (O), warning about the dangers of tobacco (W), enforcing bans on advertising, promotion and sponsorship (E) and raising taxes on tobacco (R). Results: Across countries, adolescent weekly smoking decreased from 17.7% in 2006 to 11.6% in 2014. It decreased most strongly between 2010 and 2014. Although baseline MPOWER policies were not directly associated with differences in average rates of adolescent smoking between countries, countries with higher baseline smoke-free policies (P) showed faster rates of change in smoking over the time period. Moreover, countries that adopted increasingly strict policies regarding warning labels (W) over time, faced stronger declines over time in adolescent weekly smoking. Conclusion: A decade after the introduction of the WHO MPOWER package, we observed that, in our sample of European countries and Canada, measures targeting social norms around smoking (i.e., smoke-free policies in public places and policies related to warning people about the dangers of tobacco) are most strongly related to declines in adolescent smoking.publishedVersio

    The association between MPOWER tobacco control policies and adolescent smoking across 36 countries : an ecological study over time (2006–2014)

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    Objective To examine associations over time between national tobacco control policies and adolescent smoking prevalence in Europe and Canada. Design In this ecological study, national tobacco control policies (MPOWER measures, as derived from WHO data) in 36 countries and their changes over time were related to national-level adolescent smoking rates (as derived from the Health Behaviour in School-aged Children study, 2006-2014). MPOWER measures included were: Protecting people from tobacco smoke (P), offering help to quit tobacco use (O), warning about the dangers of tobacco (W), enforcing bans on advertising, promotion and sponsorship (E) and raising taxes on tobacco (R). Results Across countries, adolescent weekly smoking decreased from 17.7% in 2006 to 11.6% in 2014. It decreased most strongly between 2010 and 2014. Although baseline MPOWER policies were not directly associated with differences in average rates of adolescent smoking between countries, countries with higher baseline smoke-free policies (P) showed faster rates of change in smoking over the time period. Moreover, countries that adopted increasingly strict policies regarding warning labels (W) over time, faced stronger declines over time in adolescent weekly smoking. Conclusion A decade after the introduction of the WHO MPOWER package, we observed that, in our sample of European countries and Canada, measures targeting social norms around smoking (i.e., smoke-free policies in public places and policies related to warning people about the dangers of tobacco) are most strongly related to declines in adolescent smoking.Publisher PDFPeer reviewe

    CLASP Constraints on the Magnetization and Geometrical Complexity of the Chromosphere-Corona Transition Region

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    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a suborbital rocket experiment that on 3rd September 2015 measured the linear polarization produced by scattering processes in the hydrogen Ly-α\alpha line of the solar disk radiation, whose line-center photons stem from the chromosphere-corona transition region (TR). These unprecedented spectropolarimetric observations revealed an interesting surprise, namely that there is practically no center-to-limb variation (CLV) in the Q/IQ/I line-center signals. Using an analytical model, we first show that the geometrical complexity of the corrugated surface that delineates the TR has a crucial impact on the CLV of the Q/IQ/I and U/IU/I line-center signals. Secondly, we introduce a statistical description of the solar atmosphere based on a three-dimensional (3D) model derived from a state-of-the-art radiation magneto-hydrodynamic simulation. Each realization of the statistical ensemble is a 3D model characterized by a given degree of magnetization and corrugation of the TR, and for each such realization we solve the full 3D radiative transfer problem taking into account the impact of the CLASP instrument degradation on the calculated polarization signals. Finally, we apply the statistical inference method presented in a previous paper to show that the TR of the 3D model that produces the best agreement with the CLASP observations has a relatively weak magnetic field and a relatively high degree of corrugation. We emphasize that a suitable way to validate or refute numerical models of the upper solar chromosphere is by confronting calculations and observations of the scattering polarization in ultraviolet lines sensitive to the Hanle effect.Comment: Accepted for publication in The Astrophysical Journal Letter

    Análisis Comparativo y Relación entre los Métodos Destructivos y no Destructivos de la Resistencia a Compresión de Concreto para la Ciudad de Arequipa

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    El presente trabajo de investigación se realizó en los laboratorios de suelos y concreto del Programa Profesional de Ingeniería Civil de la Universidad Católica de Santa María y en el laboratorio de la empresa Supermix S.A. Se desarrolla una detallada investigación sobre manuales, hojas técnicas, normas, libros, etc. de los métodos no destructivos: Esclerometria, Velocidad de pulso ultrasónico, Torrent y resistividad eléctrica para obtener resultados exactos y precisos. Se muestran los corregidos diseños de mezclas con tres diferentes tipos de cemento como son: Cemento Tipo I, Cemento Tipo HE y Cemento Tipo IP; para cinco diferentes resistencias por cada uno: 175 kg/cm2, 210 Kg/cm2, 280 kg/cm2, 350 Kg/cm2 y 420 Kg/cm2; con agregados de la Cantera La Poderosa de la Ciudad de Arequipa. Se detallan los resultados de los diseños realizados del concreto tanto en estado fresco como en estado endurecido de cada una de las probetas, así como la resistencia a la compresión, resistencia a la tracción indirecta y permeabilidad por cada tipo de cemento, resistencia de diseño e iteración de ensayo, teniendo en cuenta que se realizaron por lo menos tres iteraciones por diseño. En la investigación realizada se hace un análisis comparativo entre los métodos no destructivos: Esclerometria, Velocidad de pulso ultrasónico y resistividad eléctrica con la resistencia a la compresión, en concretos diseñados con materiales propios de la ciudad de Arequipa. Adicionalmente se hace un análisis comparativo entre los ensayos no destructivos de esclerometria y resistividad con la resistencia a la tracción indirecta en los mismos concretos diseñados con materiales existentes en nuestra ciudad. Finalmente se hace un análisis comparativo entre el ensayo de Torrent y el ensayo descrito en la norma española de permeabilidad al agua UNE-EN 12390-8 para entender más claramente los resultados obtenidos en el ensayo no destructivo de Torrent. Además en el desarrollo del presente trabajo se muestran las ecuaciones de relación entre los métodos no destructivos, la resistencia a la compresión, la resistencia a la tracción y la permeabilidad del concreto para la ciudad de Arequipa. Los resultados obtenidos en la presente investigación son aplicables en los concretos de la ciudad de Arequipa o en aquellos que cumplan con las características descritas en los siguientes capítulos. Palabras claves Resistencia a la compresión; esclerometria; número de rebotes; resistividad; resistencia a la tracción; Torrent; permeabilidad, NTP; ACI; ASTM; diamantina; pulso ultrasónico; cemento; agregados

    Morphometric and microstructural characteristics of hippocampal subfields in mesial temporal lobe epilepsy and their correlates with mnemonic discrimination.

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    Pattern separation (PS) is a fundamental aspect of memory creation that defines the ability to transform similar memory representations into distinct ones, so they do not overlap when storing and retrieving them. Experimental evidence in animal models and the study of other human pathologies have demonstrated the role of the hippocampus in PS, in particular of the dentate gyrus (DG) and CA3. Patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HE) commonly report mnemonic deficits that have been associated with failures in PS. However, the link between these impairments and the integrity of the hippocampal subfields in these patients has not yet been determined. The aim of this work is to explore the association between the ability to perform mnemonic functions and the integrity of hippocampal CA1, CA3, and DG in patients with unilateral MTLE-HE. To reach this goal we evaluated the memory of patients with an improved object mnemonic similarity test. We then analyzed the hippocampal complex structural and microstructural integrity using diffusion weighted imaging. Our results indicate that patients with unilateral MTLE-HE present alterations in both volume and microstructural properties at the level of the hippocampal subfields DG, CA1, CA3, and the subiculum, that sometimes depend on the lateralization of their epileptic focus. However, none of the specific changes was found to be directly related to the performance of the patients in a pattern separation task, which might indicate a contribution of various alterations to the mnemonic deficits or the key contribution of other structures to the function. we established for the first time the alterations in both the volume and the microstructure at the level of the hippocampal subfields in a group of unilateral MTLE patients. We observed that these changes are greater in the DG and CA1 at the macrostructural level, and in CA3 and CA1 in the microstructural level. None of these changes had a direct relation to the performance of the patients in a pattern separation task, which suggests a contribution of various alterations to the loss of function
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